The present invention relates to the tip portion of an endoscope having a tubular tip hood provided at the distal end of an insertion portion.
In endoscopic mucosectomy, the mucosa of a diseased part in a body cavity is aspirated into the tip hood of an endscope so that it becomes like a xe2x80x9cpolypxe2x80x9d in shape and its base is cut off with a high frequency snare or the like.
A problem with this technique is that when the mucosa is TO aspirated into the tip hood of the endoscope, it comes so close to the viewing window of the endoscope that endoscopic examination is not possible at all. As a result, the surgeon has to perform xe2x80x9cblindxe2x80x9d cutting with a high frequency snare or the like and he has the risk of either excising a too narrow area of the mucosa or piercing it by removing a too wide area.
An object, therefore, of the present invention is to provide the tip portion of an endoscope by which the mucosa of a diseased part aspirated into a tip hood can be safely excised or otherwise treated under examination with the endoscope.
In the present invention, an aspirated mucosa movement regulating portion is provided in a position intermediate between the distal end and the bottom of a tip hood for ensuring that the mucous membrane aspirated from the distal end of the tip hood toward an aspiration port will not get to a viewing window. Given this design, the mucous membrane will not interfere with the visual field even if it is aspirated into the tip hood, so the mucosa of a diseased part aspirated into the tip hood can be safely excised or otherwise treated under examination with an endoscope.
The present invention provides, as a preferred embodiment, the tip portion of an endoscope having a tubular tip hood provided at the distal end of an insertion portion, with at least a viewing window and an aspiration port being provided in a position corresponding to the bottom of the tip hood, characterized in that an aspirated mucosa movement regulating portion is provided in a position intermediate between the distal end and the bottom of the tip hood for ensuring that the mucous membrane aspirated from the distal end of the tip hood toward the aspiration port will not get to the viewing window.
A treatment tool projecting port for causing treatment tools to project may be provided either to double as the aspiration port or separately therefrom and this ensures that the mucosa as aspirated into the tip hood can be excised or otherwise treated by treatment tools.
If desired, the aspirated mucosa movement regulating portion may be an annular wall formed along the inner periphery of the tip hood to project inwardly. Alternatively, the aspirated mucosa movement regulating portion may be a partition provided in the intermediate position of the tip hood to project inwardly from its inner periphery so as to provide a division at least between the space ahead of the viewing window and the space ahead of the aspiration port. In yet another embodiment, the aspirated mucosa movement regulating portion may be a wall member generally parallel to the bottom plane of the tip hood, with an opening formed in an area positioned ahead of the treatment tool projecting port.
If the tip hood is transparent, the outside of it can be examined through the viewing window.
The present disclosure relates to the subject matter contained in Japanese patent application No. 2000-281156 (filed on Sep. 18, 2000), which is expressly incorporated herein by reference in its entirety.